Multiheight Properties of Moving Magnetic Features

Debi Prasad Choudhary, K. S. Balasubramaniam
2007 Astrophysical Journal  
We report on spectropolarimetric and dynamical properties of a moving magnetic feature ( MMF) around a diskcenter sunspot observed using photospheric (Fe i kk6301.5 and 6302.5) and lower chromospheric (Mg b 2 k5172.7) lines. We find that there are 33% fewer MMFs at the lower chromosphere compared to the photosphere, implying a sophisticated magnetic field geometry of tight low-level loops. A majority of bipolar MMFs are oriented with their neutral line perpendicular to the radial direction.
more » ... r "spot-ward" component has the same polarity as the sunspot. The magnetic filling factor is larger for all types of MMFs situated closer to the spot than those situated further away. Bipolar MMFs have a larger filling factor compared to the unipolar ones. Comparison of dI/dk and Stokes V profile suggests a large magnetic filling factor within the MMFs in the photosphere. Traversing individual MMFs, the Stokes V profiles vary from normal antisymmetric structures to multilobed anomalous profiles. The chromospheric counterpart of multilobed and anomalous photospheric MMF Stokes V profiles are normal and antisymmetric. This suggests that magnetic loops corresponding to MMFs in the lower atmosphere are of mixed polarity and perhaps twisted while they are relatively relaxed in the corresponding upper atmosphere. The temporal evolution of the MMFs shows a transition between anomalous and normal Stokes V profiles.
doi:10.1086/518822 fatcat:kjjdff6vh5dnhedqhm24twj5iy